There are many mechanisms available for providing an adjustable pedestal for use in tables, chairs, and other articles of furniture where adjustments in height may be desirable. One of the more common mechanisms comprises a compression spring housed in a vertical base, and a tubular member in sliding telescopic engagement with the base which is biased upwardly by the compression spring. Exertion of force over the top of the mechanism compresses the springs, lowering the pedestal into a desired position into which it can be locked. Examples of such mechanisms are disclosed in U.S. Pat. No. 1,888,478 to Steidl and U.S. Pat. No. 4,657,218 to Scheberle et al. Some of these pedestals require elaborate mechanisms to lock the telescoping members against relative movement. Such mechanisms are disclosed in U.S. Pat. No. 3,191,902 to Goller and U.S. Pat. No. 4,693,442 to Sills.
One disadvantage of all of the above-described mechanisms lies in their use of compression springs. The compression spring must be positioned at or near the bottom of the pedestal base in order for the adjustment mechanism to work. This precludes the use of a weight of any significant extent in the bottom of the base. Furthermore, the locking mechanisms generally used in adjustable pedestals are obtrusive in appearance, extending outwardly from the body of the pedestal and interfering with its appearance.
In many situations, it would be desirable to place an axially extending weight in the bottom of the pedestal in order to stabilize the article of furniture with which it is used. Also, it would be desirable to provide a locking mechanism which is unobtrusive and does not spoil the aesthetic appeal of the article of furniture. It is the solution of these and other problems to which the present invention is directed.